DALLAS (CBSNewYork/AP) — Events across the nation and around the world are marking the anniversary of President John F. Kennedy’s assassination, 50 years ago Friday.

A half-century later, the assassination still stirs quiet sadness in the baby boom generation that remembers it as the beginning of a darker, more cynical time. The anniversary ceremonies reflected that solemnity, with moments of silence, speeches by historians and, above all, simple reverence for a time and a leader long gone.

As CBS 2’s Dick Brennan reported, it’s been five decades, but a generation still remembers where they were and just how painful it was.

Bells tolled in Dealey Plaza 50 years after shots rang out there. The gunfire changed the course of a nation. Camelot, as Jackie Kennedy dubbed the era, came to a terribly tragic close, Brennan reported.

“A new era dawned and another waned a half-century ago, when hope and hatred collided right here in Dallas,” Mayor Mike Rawlings said at the largest memorial service, in Dealey Plaza, the scene of the Nov. 22, 1963, shooting.

“We watched the nightmarish reality in our front yard. Our president had been taken from us, taken from his family, taken from the world.”

Rawlings told about 5,000 people gathered under gray skies in near-freezing temperatures that the slaying prompted Dallas to “turn civic heartbreak into hard work” and helped the city to mature.

Kennedy “and our city will forever be linked in tragedy, yes,” he said. “But out of tragedy, an opportunity was granted to us how to face the future when it’s the darkest and uncertain.”

Rawlings unveiled a plaque with remarks Kennedy was supposed to deliver later that day in Dallas. His remarks were followed by a mournful tolling of bells and a moment of silence.

The plaza includes the Texas School Book Depository building, where sniper Lee Harvey Oswald perched on the sixth floor above the president’s motorcade.

A stage for the memorial ceremony, just south of the depository building, was backed with a large banner showing Kennedy’s profile. Video screens showed images of Kennedy with his family.

In a nod to Kennedy’s military service, the U.S. Naval Academy Men’s Glee Club sang at the ceremony, but an Air Force flyover was canceled because of the weather.

President Barack Obama ordered flags be lowered at government buildings to mark the anniversary, calling it a day to honor Kennedy’s memory and “celebrate his enduring imprint on American history.”

In Conn., Gov. Dan Malloy also directed that U.S. and Connecticut flags be lowered to half-staff from sunrise to sunset on Friday.

Malloy said that half a century after Kennedy’s death, his “call to action for every citizen to better our great nation and serve our fellow man” continues to inspire Americans.

“We can each do our part to carry on President Kennedy’s legacy,” he said.

As WCBS 880’s Levon Putney reported, a commemoration was held in Newark on Friday at the same site where President Kennedy delivered remarks on Oct. 12, 1962.

Solemn Events Mark 50th Anniversary Of JFK’s Assassination

“On these steps, John Kennedy, as president, appeared on Columbus Day,” organizer and former Newark Star-Ledger reporter Guy Sterling told the crowd.

Thousands crowded around the City Hall steps to hear from the 35th president on that day.

“That’s a giant and, you know, a lot of people want to walk in those steps,” interim Newark mayor Luis Quintana said.

Kennedy’s daughter Caroline is now the ambassador to Japan and she left the country last week to begin serving there.

But other family members paid tribute at the president’s grave this morning.

Shortly after sunrise, Attorney General Eric Holder paid his respects at Kennedy’s recently refurbished grave at Arlington National Cemetery.

About an hour later, Jean Kennedy Smith, 85, the last surviving Kennedy sibling, laid a wreath at her brother’s grave, joined by about 10 members of the Kennedy family. They clasped hands for a short, silent prayer and left roses as a few hundred tourists watched.

Ambassador Jean Kennedy Smith (C), sister of slain President John F. Kennedy, visits her brother’s grave with members of her family during a wreath-laying ceremony at the at Arlington National Cemetery November 22, 2013 in Arlington, Virginia. (Photo by Chip Somodevilla/Getty Images)

In Boston, Gov. Deval Patrick and Maj. Gen. Scott Rice of the Massachusetts National Guard endured a heavy rain during a wreath-laying ceremony at the Kennedy statue on the front lawn of the Statehouse. The statue, dedicated in 1990, has been largely off-limits to public viewing since security procedures put in place after the 9/11 terrorist attacks. But the area was opened to visitors Friday.

Both of Kennedy’s grandfathers served in the Massachusetts Legislature and in January 1961 the president-elect came to the Statehouse to deliver one of his most famous addresses, which came to be known as the “City on a Hill” speech, just before leaving for his inauguration in Washington.

The quiet remembrance extended across the Atlantic Ocean to Kennedy’s ancestral home in Ireland.

Earlier Thursday in Dublin, a half-dozen Irish soldiers toting guns with brilliantly polished bayonets formed a guard of honor outside the U.S. Embassy as the American flag was lowered to half-staff. An Irish army commander at the embassy drew a sword and held it aloft as a lone trumpeter played “The Last Post,” the traditional British salute to war dead. A bagpiper played laments including “Amazing Grace.” A U.S. Marine raised the flag again as the bugler sounded an upbeat “Reveille.”

More than a dozen retired Irish army officers who, as teenage cadets, had formed an honor guard at Kennedy’s graveside gathered in the front garden of the embassy in the heart of the Irish capital to remember the first Irish-American to become leader of the free world.

Kennedy’s assassination 50 years ago caused disbelief, grief and shock across the county. Texas Gov. John B. Connally, who was in the same open car as the president, was also seriously wounded.

Police captured the accused killer, Lee Harvey Oswald, but as he was being moved to a maximum security cell, he was shot and killed by Jack Ruby.

There were fresh flowers put on the grave of Lee Harvey Oswald this week, but there was no mention of him in Dealey Plaza on Friday, Brennan reported.

On Dec. 24, 1963, a month after the assassination, New York’s Idlewild Airport was re-dedicated John F. Kennedy International Airport.

It was then-Mayor Robert F. Wagner who urged the City Council to rename the airport, saying “John F. Kennedy will live on in each of us.”